"The end of the dark ages": A 3-D illustration of the "Cosmological Re-ionization" process, which occurred shortly after the birth of the universe. The first stars formed and were able to re-heat hydrogen gas, turning it into transparent plasma. The first stars, grouped in proto-galaxies, created small transparent regions around them. These regions increased in size until the neighboring regions merged together and cleared up the "fog" of neutral hydrogen, making the universe transparent to star light, as it is now.
Publication: September 23, 2004